1. Field of the Invention
The present invention relates to control devices adapted to control braking of a brushless motor, and to washing machines having the device.
2. Description of the Related Art
Already known as automatic washing machines are those of the spiral flow type wherein a washtub is housed in an outer tub and rotatable about a vertical axis, and washing machines of the drum type wherein a drum is accommodated in an outer tub rotatably about a vertical axis.
A brushless motor is used in the spiral-flow washing machine as a pulsator drive motor. The washtub and a pulsator are driven at a high speed at the same time by rotatingly driving the motor for a water extracting operation, and the motor is regeneratively braked on completion of extraction of water to apply a great braking force to the motor and bring the washtub and the pulsator motor out of rotation. On the other hand, a brushless motor is used in the drum-type washing machine for driving the drum. The drum is rotated at a high speed for a water extracting operation by rotatingly driving the motor, and the motor is regeneratively braked on completion of extraction of water to apply a great braking force to the motor and bring the drum out of rotation.
However, the conventional spiral-flow washing machine and drum-type washing machine wherein regenerative electric power is produced by the motor have a problem in that an external resistor necessary for consuming the regenerative power requires a large motor control device. The washing machines have another problem in that the need to provide an electric circuit by electronic parts of high voltage resistance renders the motor control device more expensive.